Final answer:
Carl Rogers' main motivational principle is Self-Actualization, which is part of his humanistic approach focusing on personal growth, the importance of self-concept, and the role of Unconditional Positive Regard in therapy. Correct option is C.
Step-by-step explanation:
The main motivational principle from Carl Rogers is C) Self-Actualization. This principle is part of the broader humanistic approach to psychology, in which the focus is on the growth potential of healthy individuals and the desire to become the best person one can become.
Roger's theory of personality centers around self-concept, which includes the ideal self and the real self. He believed in the importance of achieving congruence between these two selves for a greater sense of self-worth and a healthy, productive life.
To facilitate this process, Rogers advocated for Unconditional Positive Regard in therapeutic settings, a concept that involves accepting and supporting the client without any conditions or judgment. This supportive environment helps individuals work towards self-actualization, dealing with their problems effectively and growing towards their full potential.